/** Save the row at the current offset; a virtualizer's cached visible range can lag a fling. */export function resolveWorkGroupScrollAnchor(state: {  readonly data: ReadonlyArray<{ readonly id: string }>;  readonly scroll: number;  readonly positionAtIndex: (index: number) => number | undefined;}) {  if (state.data.length === 0 || !Number.isFinite(state.scroll)) return undefined;  const scrollOffset = Math.max(0, state.scroll);  let low = 0;  let high = state.data.length - 1;  let index = 0;  let rowTop = state.positionAtIndex(0);  if (rowTop === undefined || !Number.isFinite(rowTop)) return undefined;   while (low <= high) {    const middle = Math.floor((low + high) / 2);    const top = state.positionAtIndex(middle);    if (top === undefined || !Number.isFinite(top)) return undefined;    if (top <= scrollOffset) {      index = middle;      rowTop = top;      low = middle + 1;    } else {      high = middle - 1;    }  }   return {    rowId: state.data[index]!.id,    offsetWithinRow: Math.max(0, scrollOffset - rowTop),    scrollOffset,  };}